I used this one and a Platy 3.0L hoser to come up with a very nice inline filter (pop the bite valve off to use as a gravity filter). The giant bottle it comes in weighs 7 ounces, so that's been relegated to gym/kids sports use.

It is intended to be used as an inline/gravity filter (stated clearly on the box), and it includes a number of connector hoses and small zip-ties to put one together.

I've been using a platy w/ a sawyer in-line as my hydration system this year. Fill the platy and drink as usual, or hang it and remove the bite valve while I'm stopped to use it in gravity mode. It's worked very well thus far, I can barely tell the filter is there while drinking, very little flow resistance to my perception.

I wish I'd started with a 2L Hoser instead (would fit better in an outside pocket). Otherwise, I'm pretty happy with the setup. I usually only run with a single water bottle, but it's nice having camel capacity for those rare times I need it.

"I used this one and a Platy 3.0L hoser to come up with a very nice inline filter (pop the bite valve off to use as a gravity filter)."

I have almost the same setup, but with a 2L Big Zip. I like being able to open the zip end and scoop up water. I can fill the bladder in seconds and if I need more than 2L I gravity filter into another bladder. It's a great setup. No more pumping for me.